I recently had a discussion about the futuristic sims of SL and here are some of my faves...
SuffugiumThis cyberpunk sim is laid-back and filled with interesting, talented regulars. A fantastic build unto itself, explore its buildings, get
lost in the sewers or chill at the basketball court and listen to music. Look out for those probes!
Extropia CoreMost futuristic sims I came across were dystopic or post-apoc in feel. Extropia was like a retro breath of fresh air in that space age optimism kind of way. Home to
Sophrosyne's Salon--where the audience is as interesting as the topics discussed there on Saturdays--Extropia is a bright shiny Tomorrowland vision of the future and well worth a visit...
The WastelandsThis collection of post-Apocalyptic
sims is renowned for not only the ingenuity of its citizens and builds, but their true individualism and talent. Not to mention, where else can scavenging turn into survival of the fittest?
Future CityLike a Blade Runner vision,
Future City's multilayered, sky-grazing, incredible builds will have you coming back to see it again and again...Please open officially soon!
PLEASE.
InsilicoThe future is now and evolving at this
new high-in-the-sky cyberpunk build. Keep an eye on it as its community grows...
Midian CityGritty dark urban RP and one of the best builds on the grid to me...
City of Lost Angel'sOne of the now biggest (with new sims recently added), oldest and "baddest" of the dark urban future RP sims where demons, angels, lycans, vampires, humans and everyone else roam and use the CCS combat system. When the RP's good, the RP is
good there. And if you're squeamish or think you should have lots of limits or if you don't think something bad could happen to you here, why the hell are you there?
Toxian CityLike CoLA, a dark urban future sim, but personally I found the RP a bit easier to get into as a newcomer. Wear an observer tag or go ahead and put on the DCS combat system and jump right in. Maybe you'll even get to join the rest of the citizens in trying to take down one of Toxia's infamous toxic waste monsters...

Space Colony Necronom VIThis futuristic sim is set on a space station filled with slaves, cyborgs, crew members, aliens, traders and pirates. Very much a mature sim and RP experience, but it also has a very interesting HUD called NeMit, which allows you to accomplish missions without necessarily being a part of the overall RP.